This section provides background information related to the present disclosure which is not necessarily prior art. This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
Advanced water treatment methods have been the subject of significant research in recent times. Emerging threats from contaminants such as pharmaceuticals, endocrine disruptors, and industrial runoff such as recalcitrant carcinogens (e.g. textile dyes, NDMA, TCE, MTBE, PCBs and 1,4-dioxane) has highlighted the need for advanced treatment methods.
Current water treatment technology relies primarily on filtering and disinfection and in general does not address organic chemical contaminants directly. Indeed, traces of a range of soluble contaminants, though in low concentration, make it to the tap of the end user. In response, current water treatment research focuses on the removal or the safe decomposition of these emerging contaminants. While there is significant interest in bioremediation as a safe method to addressing organic contaminants, the associated long decomposition times suggests that such approaches will have to be supplemented or even replaced using advanced oxidation processes (AOPs).
AOPs involve those methods that generate large amounts of reactive oxygen species, especially the OH radical. The OH radical, though short lived, destroys organic contaminants via a process called mineralization where the final products are typically carbon dioxide, water, and inorganic salts. AOPs can be achieved conventionally. Such methods are energy intensive and require storable precursors such as hydrogen peroxide or ozone.
In recent years, the use of plasma to produce advanced oxidation products in liquid water has been the subject of many investigations. The interaction of plasma with liquid water introduces a host of oxidants in the water, such as OH, ozone, superoxide, peroxide, singlet oxygen, UV light, shock waves/ultrasound, excited nitrogen species, and solvated electrons. The presence of these advanced oxidants attacks not only soluble chemicals, but also bacteria, protozoa, and viruses. Because advance oxidation attacks the structure of these bio contagions, they cannot become immune to plasma treatment. Chlorine resistant microbes can therefore be eliminated using plasma treatments. Additionally plasma based methods can be used as a finishing process to address contaminants arising from emergency releases. The active agents produced in the plasma discharge can easily be produced with air as the feed gas, which eliminates the need for storables, such as oxygen or hydrogen peroxide. Currently, ozonation methods require onsite storage of cryogenic tanks of liquid oxygen and associated infrastructure.
Accordingly, the present teachings provide a reactor system that utilizes plasma (ionized gas) for the purpose of water purification. The plasma produces radicals that oxidize not only organic contaminants but also metal ions. The present teachings are novel in that the implementation accommodates high throughput making them applicable for point of use as well as industrial applications.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.